Cam-lapping machine



June 13, 1939. H [NDGE 2,162,662

CAM-LAPPING MACHINE Filed April f 1938 5O 0 4e 5e 31 34 3 42 32 4 I7 :2 45 38 4o 1:- a 39 3a 1 13 25 15 1] [4 Z? 74 I? gwucwbyo HERBERT 5. INDGE Show;

Patented June 13, 1939 UNITED STATES PATENT OFFICE] CAM-LAPPING MACHINE Application April 13, 1938, Serial No. 201,755

3 Claims.

The invention relates to abrading machines, and more particularly to a camshaft lapping machine. One object of the invention is to provide a cam lapping machine which shall more effectively polish the cams by producing a greater number of lapping lines in diverse directions. Another object of the invention is to provide a cam lapping device achieving additional contact with the work piece. Another object of the invention is to provide a cam lapping device achieving a higher polish on the work piece. Other objects will be in part obvious or in part pointed out hereinafter.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts. as will be exemplified in the structure to be hereinafter described, and

the scope of the application of which will be indicated in the following claims.

In the accompanying drawing illustrating one of many possible embodiments of the mechanical features of this invention, the single figure is a cross sectional view through a lapping arm and reciprocating slide of a machine according to U. S. Letters Patent No.- 2,092,734, illustrating the improved features.

The machine of the aforesaid patent comprises a camshaft lapper for simultaneously lapping all the cams and also all the bearings of an automotive camshaft. All cams and bearings are simultaneously lapped in the machine by rotation of the camshaft with individual cams in con tact with abrasive paper or cloth which is rapidly reciprocated in the direction of the axis of the camshaft, and which is moved forward and back by a master camshaft corresponding to the product camshaft, whereby to maintain contact between the abrasive paper or cloth and the several cams being lapped. The instrumentalities for lapping the bearings need not be modified according to the present invention and may be assumed to be the same as shown in the aforesaid patent.

Referring now to the single figure of the drawing, there are therein shown the two spaced bars Ill and H supporting the reciprocating slide I2. By means of cooperating dovetailed ways |3 and M, the slide I2 adjustably mounts a plurality of lapping arms I5. The ways l3 are part of the slide l2 and the ways M are part of the several arms IS. The arms can thereby be located at the desired spaced positions corresponding to the spacing of the individual cams IS on the camshaft I! to be lapped. When once the correct position of adjustment is found for each arm IS, a gib I8 is tightened by means of a screw 9 and this holds the arm l5 firmly in place.

Each of the lapping arms l5 is provided with a longitudinally extending aperture 20 which is adapted to receive a slide 2| The slide 2| is supported on its lower surface by a pair of spaced rollers 22 and 23 which are rotatably supported on 5 studs 24 and 25, respectively, this constituting an anti-friction support for the slide 2|, which is movable towards and from the camshaft H. In order to eliminate back-lash or lost motion there is provided an adjustable member 30 supporting a 10 pair of rollers 3| and 32; this adjustable member 30 being adjustable in a vertical direction by means of a screw 33 carried by a projection 34 of the lapping arm l5.

According to the aforesaid patent (issued on 15 application of myself and George E. I-Iulbert), a master camshaft 35 is rotated synchronously with the camshaft I! being lapped. According to the aforesaid Patent 2,092,734, a contact is established between a member carried by each slide 2| and the corresponding master cam 36. I provide, according to the present invention, a forked end 31 at the rear of the slide 2| and a strap 38 extending between the ends of the fork and around the master cam 36. This strap 38 is attached by means of caps 39 and screws 40 to the fork 31 and it gives to the slide 2| a somewhat different motion than the device shown in the aforesaid patent. There is provided a spring 40 (as in the patent) extending between a stud 4| attached to the slide 2| and a pin 42 attached to the lapping arm l5. The pin 42 extends between holes provided in the aperture 20 in the sides of the lapping arm I 5, and additional holes 43 are provided for adjustment. It will be seen from the foregoing that the slide 2| 35 is oscillated back and forth by the master cam 36.

At the front of each slide 2| I provide a band 45 of abrasive cloth, the abrasive side of which faces toward the front of the machine. This band 45 extends between the ends of a fork 45 formed at 40 the front of the slide 2| which fork is similar in shape to the fork 31. Caps 41 and screws 48 hold the abrasive cloth 45 in place.

There is provided also the supply reel 50 and the take-up or winding up reel 5|, both supported 45 from the slide 2| and both of which may be identical with the corresponding reels shown in the aforesaid patent.

By means of a work supporting center and a driving member, as shown in the patent, the Work piece camshaft I! is rotated. By means of suitable transmission mechanism as shown in the patent, the master camshaft 35 is rotated. The reciprocating slide 2 reciprocates as described in the patent.

The abrasive paper, commonly referred to as sandpaper, 52, with its abrasive side outermost, is held in position by the band of abrasive cloth against the cam IS. The fork 46 being substantially the same size as the fork 31 and the band 45 being substantially the same size as the band 38, and the master cam 36 being substantially the same size as the productcam I6, the motion imparted to the slide 2| is such as to keep the abrasive paper 52 in continuous contact with product cam |6 by the pressure of the spring 40. paper to follow the reciprocations of the slide 2 I. There is thus produced a lapping action upon the product camshaft and the lapping covers a Wide area at a given instant. Thereby a much more effective lapping and polishing is achieved. When.

and as the sandpaper 52 is wornout, the operator,

by the means clearly described in the patent, may

take up a little on the take-up roll 5|, the reel 5!] automatically feeding out by an equal amount.

The bands 38 and 45' are virtually slings. Preferably some means is provided to prevent side motion of the slings and to this end I provide guard plates and 56 for the bands 38 and 45, respectively, There are a pair each of the guard plates 55 and 56, fastened by screws to the sides of the slides 2|, as clearly indicated in the drawing. The width of the slides 2| should be greater than the Width of the cams l6 and 36 plus the amplitude of reciprocation and under such conditions the slings or bands are virtually prevented from sidewise motion.

The abrasive cloth 45 causes the abrasive It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As many possible embodiments may be made of the above invention and as many changes might be made in the embodiment above set forth, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawing is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. Inapparatus of the class described, a lapping arm, a slide carried by said lapping arm, forks at each end of said slide, slings carried by the forks, a master cam engaged by one sling, and sheet abrasive carried by the other sling to engage a work piece to be lapped.

2; In apparatus of the class described, a slide, means to reciprocate the slide, a sling carried by the slide, a sheet of abrasive material held by the sling whereby to lap a cam, and side guides to prevent side motion of the sling.

3. Lapping apparatus for lapping rotating bodies comprising a fork, a sling carried by the fork, a supply reel of sheet abrasive, a take-up reel for sheet abrasive, the sheet of abrasive being held by the sling in contact with the rotatable part to be lapped, and side guides held by the fork to prevent side motion of the sling.

HERBERT S, INDGE. 

